Fix exceptions of recurring all-day events

SoObjects/Appointments/SOGoAppointmentObject.m

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2007-2012 Inverse inc.
+  Copyright (C) 2007-2013 Inverse inc.
   Copyright (C) 2004-2005 SKYRIX Software AG
 
   This file is part of SOGo
@@ -107,7 +107,7 @@
                timeIntervalSinceDate: firstDate];
   if ([newOccurence isAllDay])
     {
-      nbrDays = ((float) abs (interval) / 86400) + 1;
+      nbrDays = ((float) abs (interval) / 86400);
       [newOccurence setAllDayWithStartDate: date
                                   duration: nbrDays];
     }